Mario and Sonic Run

Cinevva's analyzer read this game's design doc and its source, then wrote the brief below. "Make your own" hands it to the game creator as your opening message, so you start from a real spec rather than a one-line idea.

Create a browser-based Three.js 3D side-scrolling endless runner titled “Mario and Sonic Run.” Use a bright arcade/toy-like low-poly style with a sky-blue background and fog, soft shadows, a long green ground platform and a narrower tan/orange running road, rounded green and blue hills in the far background, and white puffy clouds. The camera is a perspective camera positioned in front/above the runner, looking along the road toward the right, with the player kept near the left side of the view while obstacles and collectibles move from right to left to create the running effect. Keep the scene full-screen and responsive.

The game begins with a dark navy rounded rectangular start overlay centered over the 3D scene. It displays the large white title “Mario and Sonic Run,” explanatory text about swapping between the high-jumping red plumber and fast blue runner, and a prominent rounded yellow-orange “Start Run” button. Behind/above the overlay, show a simple HUD across the top-left/top area: “Hero: Red Plumber,” “Score: 0,” “Rings: 0,” “Distance: 0m,” and a second line “Speed: 16.0”; also show the controls text “Space jump · Shift swap · P pause · R restart” when appropriate.

The player is an automatically running chunky stylized humanoid made from simple 3D primitives, fixed around x=-10 on the road. The default active hero is the Red Plumber: a red rectangular body, darker red flat cap, peach block face, and two chunky shoes. The alternate Blue Runner has a blue body, peach spherical head, and a large dark-blue cone/spike-like hair shape angled backward, with the same chunky shoes. Only the active character model is visible. Animate a subtle bob/tilt and alternating shoe/leg lift while running.

Implement these exact character differences: the Red Plumber has jump strength 17.5 and speed bonus -1.1; the Blue Runner has jump strength 14.8 and speed bonus +2.5. Press Space or Arrow Up to jump if the player is on the ground; vertical physics use downward acceleration about 34, and landing clamps y to zero. Press Left/Right Shift or C to swap heroes at any time after the run has started. Swapping changes the HUD hero label between “Red Plumber” and “Blue Runner” and plays a short synth-like sound. Use P to pause/resume, displaying a centered dark overlay with “Paused,” “Press P to keep running,” and a Resume button. Use R to restart after game over (and allow the start button to begin the first run).

During play, automatically spawn obstacles ahead at roughly x=36–46 and move them left at the current movement speed. Randomly choose either a green pipe or a spike block. A pipe consists of a green cylindrical column approximately 2.3 units tall with a wider green lip at its top. A spike obstacle consists of a gray rectangular base with three light-gray conical spikes. Place obstacles on the road and use simple horizontal/vertical bounding collision checks against the player; hitting either obstacle immediately ends the run and pauses the game.

Also spawn collectible gold rings ahead at roughly x=34–46, at random heights from about 1.8 to 4.3. Model each as a shiny emissive gold torus, rotate it as it travels, and allow one or sometimes two rings per spawn. Collect a ring when the player is sufficiently close horizontally and vertically; remove it, increment Rings by 1, and add 25 score. Rings and obstacles that pass far behind the player should be removed.

Start with speed 16.0 and continuously increase it by 0.18 about every 1.1 seconds. The effective movement speed is base speed plus the active hero’s bonus. Increase Distance proportionally to effective speed (approximately speed * delta time * 0.55) and Score continuously (approximately effective speed * delta time * 3), with a small additional contribution based on ring count. Update the HUD live with integer score, rings, integer distance in meters, one-decimal speed, and the active hero. Play lightweight synthesized arcade sounds for jumping, ring collection, collision, and swapping, initialized after the first click or key press.

On collision, replace the overlay contents with a dark centered “Run Over” panel showing “You reached [distance]m with [rings] rings,” “Press R or use the button to run again,” and a Restart button. Restart clears all obstacles and rings, resets score/rings/distance, speed to 16, player to the ground at the starting position, restores the Red Plumber, removes the overlay, and begins a new automatic run. Use directional lighting, hemisphere fill, shadows, fog, and a clean colorful arcade presentation; do not add gameplay systems beyond this endless running, jumping, swapping, collecting, pausing, and restarting loop.